1,721,190 research outputs found
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
New levels of language processing complexity and organization revealed by Granger causation
Full text linkGranger causation analysis of high spatiotemporal resolution reconstructions of brain activation offers a new window on the dynamic interactions between brain areas that support language processing. Premised on the observation that causes both precede and uniquely predict their effects, this approach provides an intuitive, model-free means of identifying directed causal interactions in the brain. It requires the analysis of all non-redundant potentially interacting signals, and has shown that even “early” processes such as speech perception involve interactions of many areas in a strikingly large network that extends well beyond traditional left hemisphere perisylvian cortex that play out over hundreds of milliseconds. In this paper we describe this technique and review several general findings that reframe the way we think about language processing and brain function in general. These include the extent and complexity of language processing networks, the central role of interactive processing dynamics, the role of processing hubs where the input from many distinct brain regions are integrated, and the degree to which task requirements and stimulus properties influence processing dynamics and inform our understanding of “language-specific” localized processes.National Institute on Deafness and Other Communication Disorders (U.S.) (R01DC003108
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
Molecular basis of proton uptake in single and double mutants of cytochrome c oxidase
Full text linkCytochrome c oxidase, the terminal enzyme of the respiratory chain, utilizes the reduction of
dioxygen into water to pump protons across the mitochondrial inner membrane. The principal
pathway of proton uptake into the enzyme, the D channel, is a 2.5 nm long channel-like cavity
named after a conserved, negatively charged aspartic acid (D) residue thought to help recruiting
protons to its entrance (D132 in the first subunit of the S. sphaeroides enzyme). The
single-point mutation of D132 to asparagine (N), a neutral residue, abolishes enzyme activity.
Conversely, replacing conserved N139, one-third into the D channel, by D, induces a decoupled
phenotype, whereby oxygen reduction proceeds but not proton pumping. Intriguingly, the
double mutant D132N/N139D, which conserves the charge of the D channel, restores the
wild-type phenotype. We use molecular dynamics simulations and electrostatic calculations to
examine the structural and physical basis for the coupling of proton pumping and oxygen
chemistry in single and double N139D mutants. The potential of mean force for the
conformational isomerization of N139 and N139D side chains reveals the presence of three
rotamers, one of which faces the channel entrance. This out-facing conformer is metastable in
the wild-type and in the N139D single mutant, but predominant in the double mutant thanks to
the loss of electrostatic repulsion with the carboxylate group of D132. The effects of mutations
and conformational isomerization on the pKa of E286, an essential proton-shuttling residue
located at the top of the D channel, are shown to be consistent with the electrostatic control of
proton pumping proposed recently (Fadda et al 2008 Biochim. Biophys. Acta 1777 277–84).
Taken together, these results suggest that preserving the spatial distribution of charges at the
entrance of the D channel is necessary to guarantee both the uptake and the relay of protons to
the active site of the enzyme. These findings highlight the interplay of long-range electrostatic
forces and local structural fluctuations in the control of proton movement and provide a physical
explanation for the restoration of proton pumping activity in the double mutant
Compact optical transmitters for CubeSat free-space optical communications
Full text linkWe present the results of an architectural trade study and prototype implementation of an optical transmitter suitable for resource-constrained CubeSats. Recent advances in CubeSat attitude determination and control systems have made it possible to achieve three-axis stabilization. This is essential for laser communications systems, which have challenging pointing and stability requirements. Our downlink terminal design fits in a 10 cm x 10 cm x 5 cm volume, uses < 10W of power, weighs < 1 kg, and supports data rates up to 50 Mbps. The terminal incorporates pointing, tracking and acquisition optics, an optical fine-steering mechanism, and a compact transmitter. This work focuses on the development of the transmitter for the Nanosatellite Optical Downlink Experiment (NODE). Two transmitter architectures were considered initially: direct modulation of a high-power laser diode and a master oscillator power amplifier (MOPA). The MOPA-based approach was selected and a prototype 'breadboard' was built from commercially available components. The prototype transmitter produces high fidelity (extinction ratio, ER < 33 dB) pulse position modulation (PPM) waveforms at 1550nm with 200mW average output power while consuming 6:5W of electrical power. Keywords: free-space optical communications, CubeSat, small satellites, optical transmitters, lasercomUnited States. National Aeronautics and Space Administration (Space Technology Research Fellowship Program)JPL Strategic University Research Partnership
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
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